pke: camera can track a given target

1 files changed, 68 insertions, 46 deletions

diff --git a/src/camera.cpp b/src/camera.cpp
index 75aa40f..7ee9408 100644
--- a/src/camera.cpp
+++ b/src/camera.cpp
@@ -6,6 +6,7 @@
 #include "ecs.hpp"
 #include "math-helpers.hpp"
 #include "physics.hpp"
+#include <glm/ext/quaternion_geometric.hpp>
 
 PkeCamera NullCamera {
 	.camHandle = CameraHandle_MAX,
@@ -13,11 +14,12 @@ PkeCamera NullCamera {
 	.view = PKE_CAMERA_VIEW_TARGET,
 	.stale = PKE_CAMERA_STALE_ALL,
 	.phys = {
-		.inst = nullptr,
-		.targetInst = nullptr,
+		.instHandle = InstanceHandle_MAX,
+		.targetInstHandle = InstanceHandle_MAX,
 		.constraint = nullptr,
 	},
 };
+CompInstance NullCameraInstance;
 PkeCamera *ActiveCamera = &NullCamera;
 
 const pk_handle_item_index_T MAX_CAMERAS_PER_BUCKET = 32;
@@ -25,43 +27,45 @@ BucketContainer<PkeCamera, CameraHandle> Camera_BucketContainer{};
 
 btSphereShape CameraShape{1.f};
 
-PkeCamera &PkeCamera_Register_Inner(PkeCamera &cam, const InstPos &instPos) {
+PkeCamera &PkeCamera_Register_Inner(PkeCamera &cam, CompInstance &inst, const InstPos &instPos) {
 	btVector3 gravity(0.f, 0.f, 0.f);
 
-	cam.phys.inst->physicsLayer = PhysicsCollision{0};
-	cam.phys.inst->physicsMask = PhysicsCollision{0};
+	cam.phys.instHandle = inst.instanceHandle;
+	inst.physicsLayer = PhysicsCollision{0};
+	inst.physicsMask = PhysicsCollision{0};
 
 	btVector3 localInertia(0, 0, 0);
 	CameraShape.calculateLocalInertia(instPos.mass, localInertia);
-	cam.phys.inst->bt.motionState = pk_new<btDefaultMotionState>(MemBkt_Bullet);
-	new (cam.phys.inst->bt.motionState) btDefaultMotionState(instPos.posRot);
+	inst.bt.motionState = pk_new<btDefaultMotionState>(MemBkt_Bullet);
+	new (inst.bt.motionState) btDefaultMotionState(instPos.posRot);
 
-	cam.phys.inst->bt.rigidBody = pk_new<btRigidBody>(MemBkt_Bullet);
-	new (cam.phys.inst->bt.rigidBody) btRigidBody(instPos.mass, cam.phys.inst->bt.motionState, &CameraShape, localInertia);
+	inst.bt.rigidBody = pk_new<btRigidBody>(MemBkt_Bullet);
+	new (inst.bt.rigidBody) btRigidBody(instPos.mass, inst.bt.motionState, &CameraShape, localInertia);
 
-	cam.phys.inst->bt.rigidBody->setLinearVelocity(btVector3(0,0,0));
-	cam.phys.inst->bt.rigidBody->setAngularVelocity(btVector3(0,0,0));
-	cam.phys.inst->bt.rigidBody->getCollisionShape()->setLocalScaling(instPos.scale);
-	BtDynamicsWorld->addRigidBody(cam.phys.inst->bt.rigidBody);
-	cam.phys.inst->bt.rigidBody->setGravity(gravity);
-	cam.phys.inst->bt.rigidBody->getBroadphaseProxy()->m_collisionFilterGroup = static_cast<PhysicsCollision_T>(cam.phys.inst->physicsLayer);
-	cam.phys.inst->bt.rigidBody->getBroadphaseProxy()->m_collisionFilterMask = static_cast<PhysicsCollision_T>(cam.phys.inst->physicsMask);
-	cam.phys.inst->bt.rigidBody->setUserPointer(reinterpret_cast<void *>(cam.phys.inst));
+	inst.bt.rigidBody->setLinearVelocity(btVector3(0,0,0));
+	inst.bt.rigidBody->setAngularVelocity(btVector3(0,0,0));
+	inst.bt.rigidBody->getCollisionShape()->setLocalScaling(instPos.scale);
+	BtDynamicsWorld->addRigidBody(inst.bt.rigidBody);
+	inst.bt.rigidBody->setGravity(gravity);
+	inst.bt.rigidBody->getBroadphaseProxy()->m_collisionFilterGroup = static_cast<PhysicsCollision_T>(inst.physicsLayer);
+	inst.bt.rigidBody->getBroadphaseProxy()->m_collisionFilterMask = static_cast<PhysicsCollision_T>(inst.physicsMask);
+	inst.bt.rigidBody->setUserPointer(reinterpret_cast<void *>(&inst));
 
 	return cam;
 }
 
 PkeCamera &PkeCamera_Register(const InstPos &instPos) {
 	CameraHandle cameraHandle{Buckets_NewHandle(Camera_BucketContainer)};
+	CompInstance *inst;
 
 	auto &cam = Camera_BucketContainer.buckets[cameraHandle.bucketIndex][cameraHandle.itemIndex];
 	new (&cam) PkeCamera{};
 
 	ECS_CreateEntity(&cam, nullptr);
 	cam.camHandle = cameraHandle;
-	cam.phys.inst = ECS_CreateInstance(&cam, nullptr);
+	inst = ECS_CreateInstance(&cam, nullptr);
 
-	return PkeCamera_Register_Inner(cam, instPos);
+	return PkeCamera_Register_Inner(cam, *inst, instPos);
 }
 
 PkeCamera *PkeCamera_Get(CameraHandle cameraHandle) {
@@ -83,38 +87,57 @@ PkeCamera *PkeCamera_Get(EntityHandle handle) {
 	return nullptr;
 }
 
-void PkeCamera_AttachToInstance(CameraHandle cameraHandle, CompInstance *inst) {
+void PkeCamera_TargetInstance(CameraHandle cameraHandle, CompInstance *inst) {
 	assert(cameraHandle != CameraHandle_MAX);
 	auto &cam = Camera_BucketContainer.buckets[cameraHandle.bucketIndex][cameraHandle.itemIndex];
+	CompInstance *selfInstance = ECS_GetInstance(cam.phys.instHandle);
 
 	if (cam.phys.constraint != nullptr && cam.phys.constraint != CAFE_BABE(btTypedConstraint)) {
 		CompInstance *activeInst = reinterpret_cast<CompInstance *>(cam.phys.constraint->getRigidBodyB().getUserIndex());
-		PkeCamera_DetachFromInstance(cameraHandle, activeInst);
+		PkeCamera_UntargetInstance(cameraHandle, activeInst);
 	}
 
 	btVector3 cameraOffset(0.f, -10.f, -10.f);
 
 	btTransform trfm;
+	btQuaternion bQuatRot;
 	inst->bt.motionState->getWorldTransform(trfm);
+
+	glm::vec3 gPos;
+	BulletToGlm(trfm.getOrigin(), gPos);
+	if (gPos != glm::vec3(0, 0, 0)) {
+		gPos = glm::normalize(-gPos);
+	}
+
+	glm::quat gQuatRot = glm::quatLookAt(-gPos, glm::vec3(0, -1, 0));
+	GlmToBullet(gQuatRot, bQuatRot);
+
 	trfm.setOrigin(trfm.getOrigin() + cameraOffset);
+	trfm.setRotation(bQuatRot);
 
-	cam.phys.targetInst = inst;
-	cam.phys.inst->bt.motionState->setWorldTransform(trfm);
-	cam.phys.inst->bt.rigidBody->setWorldTransform(trfm);
-	cam.phys.inst->bt.rigidBody->setLinearVelocity(btVector3(0,0,0));
-	cam.phys.inst->bt.rigidBody->setAngularVelocity(btVector3(0,0,0));
-	cam.phys.inst->bt.rigidBody->activate();
+	cam.phys.targetInstHandle = inst->instanceHandle;
+	selfInstance->bt.motionState->setWorldTransform(trfm);
+	selfInstance->bt.rigidBody->setWorldTransform(trfm);
+	selfInstance->bt.rigidBody->setLinearVelocity(btVector3(0,0,0));
+	selfInstance->bt.rigidBody->setAngularVelocity(btVector3(0,0,0));
+	selfInstance->bt.rigidBody->activate();
 
 	assert(cam.phys.constraint == nullptr || cam.phys.constraint == CAFE_BABE(btTypedConstraint));
+	/* 2025-01-14 JCB
+	 * This was throwing bullet3 errors, so I've decided to split the work.
+	 * This commit completes the 'targeting' task, where a camera tracks a target.
+	 * This may or may not make a good starting point for the 'following' task.
+	 *
 	cam.phys.constraint = pk_new<btTypedConstraint>(MemBkt_Bullet);
-	new (cam.phys.constraint) btPoint2PointConstraint(*cam.phys.inst->bt.rigidBody, *inst->bt.rigidBody, btVector3(0.f, -1.f, -1.f), cameraOffset);
+	new (cam.phys.constraint) btPoint2PointConstraint(*selfInstance->bt.rigidBody, *inst->bt.rigidBody, btVector3(0.f, -1.f, -1.f), cameraOffset);
 	BtDynamicsWorld->addConstraint(cam.phys.constraint);
+	*/
 
 	cam.view = PKE_CAMERA_VIEW_TARGET;
 	cam.stale = PKE_CAMERA_STALE_POSROT;
 }
 
-void PkeCamera_DetachFromInstance(CameraHandle cameraHandle, CompInstance *inst) {
+void PkeCamera_UntargetInstance(CameraHandle cameraHandle, CompInstance *inst) {
 	assert(cameraHandle != CameraHandle_MAX);
 	auto &cam = Camera_BucketContainer.buckets[cameraHandle.bucketIndex][cameraHandle.itemIndex];
 	BtDynamicsWorld->removeConstraint(cam.phys.constraint);
@@ -155,8 +178,8 @@ void PkeCamera_Destroy(CameraHandle cameraHandle) {
 	cam.type = PkeCameraType_MAX;
 	cam.view = PkeCameraView_MAX;
 	cam.stale = PkeCameraStaleFlags_MAX;
-	cam.phys.inst = CAFE_BABE(CompInstance);
-	cam.phys.targetInst = CAFE_BABE(CompInstance);
+	cam.phys.instHandle = InstanceHandle_MAX;
+	cam.phys.targetInstHandle = InstanceHandle_MAX;
 	cam.phys.constraint = CAFE_BABE(btTypedConstraint);
 }
 
@@ -175,23 +198,21 @@ PkeCamera *PkeCamera_GetCameras(int64_t bucketIndex, int64_t &count) {
 
 void PkeCamera_Init() {
 	Buckets_Init(Camera_BucketContainer, MAX_CAMERAS_PER_BUCKET);
-	NullCamera.phys.inst = pk_new<CompInstance>();
+	memset(&NullCameraInstance, 0, sizeof(NullCameraInstance));
 	InstPos instPos{
 		.scale = btVector3(1.f, 1.f, 1.f),
 		.mass = 1.f,
 	};
-	PkeCamera_Register_Inner(NullCamera, instPos);
+	PkeCamera_Register_Inner(NullCamera, NullCameraInstance, instPos);
 }
 
 void PkeCamera_Teardown() {
+	BtDynamicsWorld->removeRigidBody(NullCameraInstance.bt.rigidBody);
+	pk_delete<btDefaultMotionState>(NullCameraInstance.bt.motionState, MemBkt_Bullet);
+	pk_delete<btRigidBody>(NullCameraInstance.bt.rigidBody, MemBkt_Bullet);
+	NullCameraInstance.bt.motionState = CAFE_BABE(btDefaultMotionState);
+	NullCameraInstance.bt.rigidBody = CAFE_BABE(btRigidBody);
 	Buckets_Destroy(Camera_BucketContainer);
-	BtDynamicsWorld->removeRigidBody(NullCamera.phys.inst->bt.rigidBody);
-	pk_delete<btDefaultMotionState>(NullCamera.phys.inst->bt.motionState, MemBkt_Bullet);
-	pk_delete<btRigidBody>(NullCamera.phys.inst->bt.rigidBody, MemBkt_Bullet);
-	NullCamera.phys.inst->bt.motionState = CAFE_BABE(btDefaultMotionState);
-	NullCamera.phys.inst->bt.rigidBody = CAFE_BABE(btRigidBody);
-	pk_delete<CompInstance>(NullCamera.phys.inst);
-	NullCamera.phys.inst = CAFE_BABE(CompInstance);
 }
 
 void PkeCamera_Tick(double delta) {
@@ -210,16 +231,17 @@ void PkeCamera_Tick(double delta) {
 		long itemCount = Camera_BucketContainer.pkeHandle.bucketIndex == b ? Camera_BucketContainer.pkeHandle.itemIndex : Camera_BucketContainer.limits.itemIndex;
 		for (pk_handle_item_index_T i = 0; i < itemCount; ++i) {
 			auto &cam = bkt[i];
-			if (cam.handle == EntityHandle_MAX) {
+			if (cam.handle == EntityHandle_MAX || cam.phys.instHandle == InstanceHandle_MAX) {
 				continue;
 			}
-			if (cam.phys.inst != nullptr && cam.phys.inst != CAFE_BABE(CompInstance) && cam.phys.inst->isNeedingUpdated == true) {
-				cam.stale = cam.stale | PKE_CAMERA_STALE_POSROT;
-				cam.phys.inst->isNeedingUpdated = false;
-			}
-			if (cam.phys.targetInst != nullptr && cam.phys.targetInst != CAFE_BABE(CompInstance) && cam.phys.targetInst->isNeedingUpdated == true) {
+			CompInstance *inst = ECS_GetInstance(cam.phys.instHandle);
+			assert(inst != nullptr);
+			if (inst->isNeedingUpdated == true) {
 				cam.stale = cam.stale | PKE_CAMERA_STALE_POSROT;
+				inst->isNeedingUpdated = false;
 			}
+			if (cam.phys.targetInstHandle == InstanceHandle_MAX) continue;
+			cam.stale = cam.stale | PKE_CAMERA_STALE_POSROT;
 		}
 	}
 }